linux-mips
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Re: r4600 flag

To: Thiemo Seufer <ica2_ts@csv.ica.uni-stuttgart.de>
Subject: Re: r4600 flag
From: Ralf Baechle <ralf@oss.sgi.com>
Date: Tue, 31 Jul 2001 11:25:31 +0200
Cc: linux-mips@oss.sgi.com
In-reply-to: <20010731092822.L27008@rembrandt.csv.ica.uni-stuttgart.de>; from ica2_ts@csv.ica.uni-stuttgart.de on Tue, Jul 31, 2001 at 09:28:22AM +0200
References: <3B664857.4040100@pacbell.net> <20010731092822.L27008@rembrandt.csv.ica.uni-stuttgart.de>
Sender: owner-linux-mips@oss.sgi.com
User-agent: Mutt/1.2.5i
On Tue, Jul 31, 2001 at 09:28:22AM +0200, Thiemo Seufer wrote:

> > The la macro is split into a lui and a daddiu. The daddiu is not correct 
> > for a mips32 cpu. Getting rid of the -mcpu=4600 fixes the problem and 
> > the daddiu is then changed addiu.
> 
> This is IIRC a known bug in at least current binutils CVS, a patch
> to fix it really was already discussed.

Is this macro expaned by the compiler or assembler?  Just -mcpu=r4600
should not make cc1 generate any instructions beyond MIPS I.

In the past we already had inline assembler fragments that left the assembler
in .misp3 mode thus resulting the rest of the file bein assembled in
mips3 mode.

> > Is there a truly correct -mcpu option for a mips32 cpu?

None is really good, none is really bad ...

> In theory, no -mcpu option (which is to be deprecated in
> favor of -march/-mtune) and -mips32 as ISA flag _should_ work.
> 
> In practice, the patch which adds this to gas was discussed on the
> binutils list the last days and is likely to go in CVS
> today or tomorrow.

  Ralf

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